Interview/ Kumaraswamy Thangaraj CSIR Bhatnagar Fellow, Centre for Cellular & Molecular Biology, Hyderabad
Q/ How do you see yourself—historian, physician or scientific detective?
This field demands input from historians, archaeologists, anthropologists and medical geneticists. I see myself as a combination of all.
Q/ Has any discovery genuinely surprised you?
It happens constantly. Take the Andamanese—phenotypically they resemble Africans, so we expected their genomes to match. But their long isolation produced a unique set of mutations found nowhere else in the world, not even in Africa. Medical genetics throws such surprises.
Q/ There are studies about migration to India. Did migration also flow outward?
Yes. The first out-of-Africa coastal migration is clear—some groups stayed in southern India, some reached the Andamans, others continued to Australia. Australian Aborigines are part of that same movement. We have also shown that European Roma migrated from India roughly 1,400 years ago, consistent with historical evidence of Indian migration to Indonesia and elsewhere.
Q/ Is there a genetic explanation for the high rates of diabetes and cardiovascular disease in India?
The “thrifty gene hypothesis” offers one explanation. Our genomes evolved to metabolise small quantities of food because our ancestors lived under scarcity. Today, diets are rich in sugar, fat and carbohydrates, but our metabolism has not caught up. Add to that a dramatic drop in physical activity, and the result is metabolic overload. Evolutionary adaptation to richer diets could theoretically occur over a very long period, but we can’t predict when.
Q/ Should healthy people get genetic tests?
If a disease runs in the family, yes. For otherwise healthy individuals, more caution is needed. Carrying a mutation does not guarantee that the disease will develop; other genes may suppress it. Telling a healthy person they carry a cancer or cardiac mutation can cause significant psychological harm. These findings must be handled responsibly.
